Mashed potatoes come differently here. Traditionally this dish is a combination of mashed potatoes with softened and crunchy savoy cabbage, but added leek and garlic as well can define it as Colcannon, which is a traditional Irish dish.
- 5 medium Yukon Gold potatoes (about 1¾ pounds)
- Kosher salt
- 6 tablespoons unsalted butter, divided
- 2 leeks, white and pale-green parts only, sliced in half lengthwise, thinly sliced crosswise
- 2 garlic cloves, thinly sliced
- 2 cups shredded savoy cabbage, divided
- 1¼ cups milk
- ½ cup heavy cream
- Freshly ground black pepper
- 1 scallion, thinly sliced
Cover potatoes with water in a small pot; season with salt. Bring to a boil over medium-high heat, then reduce heat and simmer until a paring knife slides easily through the flesh, 30–40 minutes. Drain, let cool slightly, and peel.
Transfer colcannon to a large serving bowl. Top with remaining 2 Tbsp. butter and sprinkle with scallion.